Do your great-grandmother’s descendants have the Mongolian mark that native American babies have?
I had to look up what a Mongolian mark was, as I was unfamiliar with the term. I'm not sure about my brothers and sister (will soon ask them!), but I do have a mark on my right calf that would probably qualify as such. My children do not appear to have inherited any Indian traits, other then my daughter tans very quickly and never gets sun burnt even though she is blond.
My granddaughter had one of those.